Investigating the Mechanism of Sup35 Prion Curing by Excess Hsp104

研究过量 Hsp104 固化 Sup35 朊病毒的机制

• 批准号: 8141661
• 负责人: Courtney Lee Klaips
• 金额: $ 2.78万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8141661
• 关键词: Adopted; Aging; Alzheimer' s Disease; Appearance; Biological Models; Cell physiology; Cells; Characteristics; Complex; Development; Disease; Ensure; Equilibrium; Eukaryota; Event; Future; Glean; Huntington Disease; In Vitro; Lead; Mammals; Modeling; Molecular; Molecular Chaperones; Nature; Outcome; Parkinson Disease; Pathology; Pathway interactions; Phenotype; Predisposition; Prions; Process; Protein Dynamics; Proteins; Quality Control; Role; Saccharomyces cerevisiae; Specific qualifier value; Testing; Therapeutic Intervention; Time; Work; Yeasts; age related; aggregation pathway; base; case control; conformer; cytotoxicity; daughter cell; fungus; human disease; in vivo; insight; overexpression; protein aggregate; protein folding; protein function; protein misfolding; response; sup35; yeast prion

DESCRIPTION (provided by applicant): In most cases, proteins adopt a single three-dimensional fold that specifies their functions in vivo. There are several protein quality control pathways that help to ensure that proteins adopt their proper fold and that improperly folded proteins are degraded. The breakdown of these protein quality control pathways, particularly as a result of aging, can lead to a number of devastating human diseases. The most severe of these disorders, such as Alzheimer's, Parkinson's and Huntington's diseases are caused by the self- perpetuating misfolding and aggregation of otherwise normal cellular proteins. The appearance and persistence of these protein aggregates can lead to the disease state by inhibiting the function of the aggregated protein, or by producing toxic aggregates. In either case, control of the aggregation pathway is a key determinant in the progression of pathology. While these disease-associated aggregates are stable in vitro, the same complexes appear to be dynamic in vivo, suggesting that existing cellular mechanisms could be exploited through therapeutic intervention to target these pathogenic complexes for clearance. Perhaps the best-studied example of misfolded protein dynamics involves the yeast prion protein Sup35. Sup35 forms self-perpetuating, heritable aggregates that are continually remodeled by the molecular chaperone Hsp104. A similar remodeling activity is considered essential for the development and spread of self-perpetuating protein aggregates in higher eukaryotes. When Hsp104 levels are elevated in yeast, Sup35 prion aggregates, but not those comprised of other prion proteins, are lost over time. While in vitro studies suggest this effect results from resolubilization of aggregated protein, the available in vivo studies do not support this hypothesis. To elucidate the molecular basis of this process, I will determine both the characteristics of protein aggregates that confer susceptibility to excess Hsp104 and the mechanism by which excess Hsp104 leads to a loss of these complexes. Together, these studies will elucidate the dynamic equilibrium between soluble and aggregated forms of a misfolded protein in vivo, uncover the role of protein disaggregation in this process, and highlight key events in this pathway that could be exploited for therapeutic intervention. Many devastating aging-related diseases are caused by the breakdown of protein quality control pathways that lead to the buildup of toxic protein aggregates. The proposed work aims to elucidate the mechanism of action of a chaperone protein that functions in removing aggregated proteins from cells, providing insights into a pathway that could potentially be the target of future therapies.

描述(申请人提供)：在大多数情况下，蛋白质采用单一的三维折叠，该折叠指定了它们在体内的功能。有几种蛋白质质量控制途径可以帮助确保蛋白质采用其适当的折叠，并确保不正确折叠的蛋白质被降解。这些蛋白质质量控制途径的崩溃，特别是衰老的结果，可能会导致许多毁灭性的人类疾病。其中最严重的疾病，如阿尔茨海默氏症、帕金森氏症和亨廷顿病，是由正常细胞蛋白质的自我永久错误折叠和聚集引起的。这些蛋白质聚集体的出现和持续存在可能通过抑制聚集蛋白的功能或通过产生有毒聚集体而导致疾病状态。在任何一种情况下，聚集途径的控制都是病理进展的关键决定因素。虽然这些与疾病相关的聚集体在体外是稳定的，但同样的复合体在体内似乎是动态的，这表明可以通过治疗干预利用现有的细胞机制来靶向这些致病复合体进行清除。也许研究得最好的错误折叠蛋白质动力学的例子涉及酵母普里恩蛋白Sup35。Sup35形成自我保持的、可遗传的聚集体，这些聚集体不断被分子伴侣Hsp104重塑。在高等真核生物中，类似的重塑活动被认为对自我永久化蛋白质聚集体的发展和传播是必不可少的。当酵母中的Hsp104水平升高时，随着时间的推移，Sup35 Pron聚集体会丢失，但不会丢失由其他Prion蛋白组成的聚集体。虽然体外研究表明这种效应是由于聚合蛋白的分解所致，但现有的体内研究并不支持这一假说。为了阐明这一过程的分子基础，我将确定使人对过量Hsp104敏感的蛋白质聚集体的特征，以及过量Hsp104导致这些复合体丢失的机制。总之，这些研究将阐明体内错误折叠蛋白质的可溶形式和聚集形式之间的动态平衡，揭示蛋白质解聚在这一过程中的作用，并强调这一途径中可用于治疗干预的关键事件。许多与衰老相关的破坏性疾病是由蛋白质质量控制途径的崩溃引起的，这些途径导致有毒蛋白质聚集体的积累。这项拟议的工作旨在阐明伴侣蛋白的作用机制，该蛋白具有从细胞中移除聚集蛋白的功能，为可能成为未来治疗目标的途径提供见解。